1. Field of the Invention
The invention relates in general to a circuit adjusting method and an adjusting circuit, and more particularly to an adjusting method and an adjusting circuit for adjusting driving ability of an output buffer.
2. Description of the Related Art
In the modern age having the technological development, which changes with each passing day, existing output buffers have been widely used in various occasions. The present output buffer adjusts an output signal from its initial level to a readable high reference level or a readable low reference level according to an input signal in a signal value determining period. In other words, the output buffer needs to have a specific output slew rate so as to adjust the level of the output signal in the signal value determining period.
Generally speaking, the output slew rate of the output buffer relates to parameters, such as process, voltage, temperature and capacitance-loading (PVTC) parameters. Conventionally, the PVTC parameters for the circuit of the output buffer are designed in the worst case circuit environment in order to ensure that the output buffer can adjust the level of the output signal in the signal value determining period and any circuit environment.
In the typical condition, however, most circuit environments, to which the output buffer is actually applied, are much better than the worst case circuit environment. Therefore, the conventional output buffer, which is designed according to the worst case, can provide the circuit driving ability far greater than that required in this application environment. So, the output buffer has the drawbacks including the higher power noise, the higher power consumption and the higher electromagnetic interference (EMI).